On the day of the crash, Wright texted and then met Pierce at Darfield. When the two cars set off, with Pierce driving the other vehicle, Wright said he was aware that Pierce was disqualified and he wasn't sure how much he had had to drink.

Witnesses earlier in today's trial spoke of seeing Pierce slurring, stumbling, or staggering at the party, and one said she tried for 15 minutes to get the keys off him so that he could not drive.

The Crown alleges he drove away from the party to where he was flatting in Darfield, then drove from there to where the crash occurred near West Melton.

Angela Pohatu, who helped set up for the party and stayed through the day and evening, described Pierce as being "happy and jovial", and said he was not slurring but "there was obvious drunkenness there".

Anneke Pine, of Spreydon, was one of two women who tried to stop Pierce and Frost driving from the party in the 4WD.

She had seen them staggering across the road, and said Pierce "seemed drunk enough" for her to speak to him about driving.

Frost was so drunk that she could not understand his slurred speech.

Pierce denies alternative charges of causing Frost's death by driving when he was under the influence of drink to such an extent that he was incapable of having proper control, and that he caused the death by careless driving while under the influence of drink.

The third charge accuses him of failing to render "all practicable assistance" to Frost at the crash scene. He also denies that charge.